1. Field of the Invention
The present invention relates to a method of diagnosing inverter trouble, more particularly to a method of diagnosing inverter trouble, which can improve convenience in use and safety of a user by detecting and notifying the user of an error of a switching device used for outputting AC voltage of an inverter and an earth fault of an output of the inverter when applying power to the inverter.
2. Description of the Prior Art
As generally known in the art, an inverter has a fault protective function, so an error of the inverter is instantly displayed if malfunction of the inverter has been detected in response to an operating signal applied to the inverter after power is applied to the inverter.
FIG. 1 is a block view showing a structure of a conventional 3-phase switch used for outputting AC voltage of an inverter. The conventional 3-phase switch includes positive and negative voltage lines 11 and 12 for supplying DC voltage 13 to the inverter, U and U/drives 14 and 15 for driving U-phase positive and negative switching devices of the inverter, V and V/drives 16 and 17 for driving V-phase positive and negative switching devices of the inverter, W and W/drives 18 and 19 for driving W-phase positive and negative switching devices of the inverter, an earth fault detecting section 20 for outputting a fault signal by detecting an earth fault from U-phase, V-phase and W-phase outputs, and an over current detecting section 21 for protecting switching devices from over current and an error.
Hereinafter, a conventional method for managing the conventional inverter having an AC output section as described above will be explained with reference to FIG. 2.
FIG. 2 is a flow chart showing a conventional method for managing the conventional inverter. As shown in FIG. 2, the conventional method includes the steps of applying power to the inverter (S101), initializing operating conditions of the inverter for managing the inverter and waiting for a normal operation (S102), receiving an inverter operating order from a user (S103), detecting a fault of the inverter while operating the inverter (S104), and notifying the user of the fault of the inverter while stopping the operation of the inverter if the fault is detected during the operation of the inverter (S105).
According to the conventional inverter managing method, when the user applies power to the inverter, various operating conditions of the inverter are initialized. After the initializing step, the inverter waits for a normal operation.
Then, the user inputs the operating order into the inverter so that the inverter is operated according to the operating order of the user. If the user does not input the operating order, the inverter continuously waits for the operating order. That is, the inverter is operated in response to the operating order to the user and a fault inspection for the inverter begins simultaneously with the operation of the inverter.
Accordingly, the inverter is continuously operated if the fault does not occur in the inverter while the fault inspection is being continuously carried out. If the fault occurs in the inverter, the operation of the inverter stops and the fault is displayed.
However, according to the conventional method, any fault of components and any earth fault of the output of the inverter may be detected only when the user inputs the operating order into the inverter after power has been applied to the inverter, so a dependence rate for a protective circuit and risk of the user may increase. In addition, the fault can be detected only when the inverter is operated.
That is, the conventional inverter may display the fault according to a protective function of the inverter if the inverter represents the fault in response to the operating order of the user after power has been applied to the inverter. Accordingly, the user cannot recognize the fault if the fault occurs in the inverter before the operating order of the user has been inputted into the inverter in a state in which power has been applied to the inverter. Thus, the user is exposed to an accident if the fault of the inverter occurs in such circumstances.